Electric rotisserie

ABSTRACT

A cooking apparatus is provided in which a cooking cavity is defined by a front wall, a back wall, two opposing sidewalls, a ceiling, and a floor, a substrate for supporting a food item, substantially enclosed by the cavity, a plurality of heating elements located proximal to the ceiling of the cavity, a dividing member in which a first portion is disposed from the back wall of the cavity, a second portion is disposed from the ceiling of the cavity, wherein the first portion and second portion define a plenum that extends from an area proximal to the bottom of the back wall to an area proximal to the top of the front wall; and a void is located in the second portion intermediate of the plurality of heating elements and the substrate; and at least one air handling unit located on the top portion of the cavity.

BACKGROUND OF THE INVENTION

1. Field of the invention

This invention is directed to an electric powered heating apparatus, and specifically, this invention relates to an electric cooking apparatus wherein a single heat source provides both radiative and convective heating.

2. Background of the Invention

Rotisserie ovens provide an efficient way to identically cook several food items at the same time. Such food items include red meat, fish, fowl, vegetables and combinations thereof. Chicken remains one of the most popular rotisserie-cooked foods. Rotisserie cooking begets the succulent meat, crisp skin, and caramelized appearance sought by chicken aficionados everywhere. Consistently and economically producing these visual, textural, and flavorful characteristics is an art form. It requires careful cooking and a balance between convection and thermal radiation.

Convection is a form of heating in which heat is transferred as the result of the movement of particles within a fluid. In an oven, that fluid is air, wherein the air molecules carry heat from the heating elements to the relatively colder food.

Thermal radiation is energy produced in the form of electromagnetic waves emanating from the thermal motion of charged particles in matter. Heating elements provide thermal radiation in an oven. Most of that radiation is infrared.

Convection and thermal radiation work together to cook food in an oven. Food in an oven is at a temperature less than the air temperature in the oven. As heat naturally migrates from hot to cold areas, air immediately adjacent the food will be cooler because the heat from the air will be absorbed by the food. This cold air layer is continually replaced by circulating hot air in the oven. So, the food is constantly absorbing more heat, resulting in the food item heating up to the desired temperature. The continuous replacement of the air around the food item also produces a wicking effect, which tends to transport moisture away from the surface of the food.

Ideally, convective heating is aided by thermal radiation. As the heating elements rise in temperature, the thermal motion of charged particles within the heating element produces emissions of electromagnetic infrared radiation. This radiation contacts the food and heats it. Thermal radiation is directional, meaning that the emissions of energy are not affected by air currents within the oven. However, it can be blocked or absorbed by objects between the source of the radiation and the food item.

Convective and radiative heating simultaneously cook the food, and each form of heating shares some responsibility for producing the crisp, browned skin, which is visually and texturally appealing. Radiative heating does not involve mass transfer, so it heats the surface without wicking moisture from the surface. As a result, radiant heat provides more heat energy to the surface of the food items without drying the surface too quickly. If the surface dries too quickly, not only does the final product lose its succulence, but thermal conduction within the food item is slowed. Therefore, convective and radiative heating need to be balanced. Balanced heating will reduce the cooking time and prevent the food from becoming too dry from convective heating or too charred from radiative heating.

Consistently providing balanced heating environs remains elusive in the food arts. Most prior art ovens either draw air from the sides and vent it through the top of the chamber or pull air through the top and vent it through the sides. Thus, the air at the bottom of the chamber is not replaced and a noticeable temperature gradient develops.

Another concern in rotisserie ovens is grease splatter. Grease on the heating elements causes hot spots to form there. These hot spots burn hotter than the surrounding areas. The grease acts as an insulator on the heating elements, increasing the localized Watt density (i.e., the energy dissipated per second over a unit area) experienced by the heating element. This uneven heating causes thermal stresses, which result in the eventual failure of the element. Aside from grease, other matter generated during heating processes (e.g. during non-cooking protocols) may land on the element, that other matter being cleaning agents and cooking by-products.

Conventional ovens attempt to minimize grease splatter by shielding the heating element. This option, however, limits the effectiveness of the heating element to providing convective heat, not infrared radiation. Often then, radiative heating is completely forgone, or a separate, second heating element must be provided to supply thermal radiation for crisping. Even if these separate radiation heating elements are shielded from spatter, their failure rate is still quite high when compared to the radiative heat source, and so, they have to be replaced often. Besides failure from grease splatter, these elements also are easily mishandled, and failure can result from oil deposits from a user's skin left during installation, breaking during installation or cleaning, or burnout.

Therefore, a need exists in the art for a rotisserie oven in which a single element can effectively provide both convective and radiative heating without that heating element being susceptible to failure due to grease splatter. The oven should comprise relatively inexpensive components. Further, the element should confer ease of access to the componentry for cleaning and repair.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a heating apparatus that overcomes many of the drawbacks of prior art ovens.

Another object of the present invention is to provide a cooking apparatus in which a single heating source is simultaneously used for both radiative and convective heating. A feature of the present invention is an air plenum that allows for improved circulation of the heated air within the oven. Another feature of the present invention is an adjustable aperture or window in the upper portion of the plenum that exposes the heating elements. An advantage of the present invention is that the air plenum allows the heating element to provide convective heating, while the void allows thermal radiation to contact the food.

A further object of the present invention is to provide an improved system of air circulation within a cooking apparatus. A feature of the present invention is an air plenum that draws lower temperature air from the bottom of the cooking chamber, directs that air over the heating element, and then expels the heated air at the top of the chamber. An advantage of the present invention is that the air within the entire chamber is continually replaced, providing a more homogeneous cooking temperature.

Yet another object of the present invention is to reduce the failure rate of heating elements within the cooking chamber. A feature of the present invention is that the single heating source is partially shielded from grease splatter by an air curtain created by convective heat flow. Another feature of the present invention is heating elements with a Watt density lower than conventional heating elements. An advantage of the present invention is that the heating elements, though exposed, do not suffer burnout from grease splatter.

Another object of the present invention is to provide a more reliable cooking apparatus. A feature of the present invention is that only a single heat source is used for both radiative and convective heating. Because only a single source is used for both convective and radiative heating, a second heating element is not needed to provide radiative heating. An advantage of the present invention is that the oven is more economical to maintain, requires less downtime to replace parts, and consistently provides uniform results.

Still another object of the present invention is to provide a cooking apparatus that produces a food item with ideal physical properties without increasing the cooking time. A feature of the present invention is that contributions from convective and radiative heating are utilized and balanced to quickly and evenly cook food items. An advantage of the present invention is that items such as whole chickens retain their succulence, while also achieving a browned, crisped skin.

Briefly, the invention provides a cooking apparatus, said apparatus comprising: a cooking cavity, wherein the cavity is defined by a front wall, a back wall that opposes the front wall, two opposing side walls, a ceiling, and a floor that opposes the ceiling; a substrate for supporting a food item, the substrate substantially enclosed by the cavity; a plurality of heating elements located proximal to the ceiling of the cavity; a dividing member, said dividing member comprising a first portion spatially disposed from the back wall of the cavity; a second portion spatially disposed from the ceiling of the cavity, wherein the first portion and second portion are continuous and define a plenum that extends from an area proximal to the bottom of the back wall to an area proximal to the top of the front wall; and a void region located in the second portion, wherein the void region is intermediate the plurality of heating elements and the substrate; and at least one air handling unit located on the top portion of the cavity proximal to the back portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention together with the above and other objects and advantages will be best understood from the following detailed description of the preferred embodiment of the invention shown in the accompanying drawings, wherein:

FIG. 1 is perspective view of the cooking apparatus in accordance with the features of the present invention;

FIG. 1A is a front view of the cooking apparatus;

FIG. 1B is a side view of the cooking apparatus;

FIG. 2 is a sectional view of the cooking apparatus taken along line 2-2 as shown in FIG. 1B;

FIG. 3 is a sectional view of the cooking apparatus taken along line 3-3 as shown in FIG. 1A;

FIG. 4 is a view of the ceiling of the cooking apparatus taken along line 4-4 as shown in FIG. 3;

FIG. 5 is a sectional view of the cooking apparatus taken along line 5-5 as shown in FIG. 1A;

FIG. 6 is a view of the underside of the second portion of the dividing member taken along line 6-6 as shown in FIG. 1A;

FIG. 7 is a sectional view of an embodiment of the cooking apparatus featuring sliding panels, in accordance with the features of the present invention;

FIGS. 8A-E depict airflow patterns for a variety of angled void edges;

FIG. 9 depicts and alternate embodiment of the cooking apparatus featuring a transparent material covering the void, in accordance with the features of the present invention; and

FIG. 10 is a perspective view of an alternate embodiment, featuring a pass-through design, in accordance with the features of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings.

As used herein, an element recited in the singular and preceded with the word “a” or “an” should be understood as not excluding plural said elements, unless such exclusion is explicitly stated. Furthermore, the references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.

The present invention is directed to an electric heating apparatus that allows for a single heat source to provide both radiative and convective heating.

An embodiment of the invention comprises an electric rotisserie wherein both types of heating interact with water in the food. For example, poultry, like all meats, is comprised mostly of water, and water absorbs the highest amount of energy from radiation having a wavelength of approximately 3-10 μm, which is in the infrared spectrum. Thus, effective radiative heating should be in the infrared spectrum and preferably in the 3-10 μm wavelength range.

The electric rotisserie features a channel (such as a plenum) that provides a means for directing or circulating heated fluid such as air within an enclosed cooking space. In the primary embodiment, a region of the plenum intermediate of the heat source and the food defines a void, window or opening or a plurality of openings such that the radiant heat from the heating elements is emitted through that void(s) and onto the food. Furthermore, the circulation of the air in the plenum serves as an air curtain around the heating elements, substantially reducing the amount of grease that contacts the heating elements.

In another embodiment, the portion of the plenum that is intermediate of the heating elements and food comprises a transparent material, such that the thermal radiation from the heating element travels through the transparent material. As such, the transparent material allows passage of thermal radiation, and confers visual inspection of the heating element through the plenum, while simultaneously preventing fluid communication between the food and the heating element. Concomitantly, the transparent material protects the heating element from grease splatter.

The present invention will be described in terms of a rotisserie oven. However, this description is meant to be illustrative and non-limiting. The features of the present invention could apply to other cooking apparatuses as well and to heating units generally.

As can be seen in FIG. 1, an embodiment of the present invention is a cooking apparatus designated as numeral 10 comprising a housing 12 (thereby defining an outside surface) mounted on a base 13. The housing 12 features a door 14 with a door handle 15 and a window 16. As depicted in FIG. 1, the door 14 opens about the vertical axis on the left side of the cooking apparatus; however, the door 14 could open about a horizontal axis, or about multiple vertical axes as would be the case if the oven had French doors. On the right hand side of the housing 12 is a display unit 17 defining a control pad 18; although the display unit 17 and control pad 18 could be a single, integrated unit, such as a touchscreen. The control pad 18 and display unit 17 may also optionally feature any or all combinations of a mechanical timer, a mechanical thermostat, and an electronic thermostat. On the interior of the cooking apparatus 10 is a spit assembly 19, which is depicted in phantom through the window 16.

The spit assembly 19 comprises individual spits removably received by two plates, and a motor to drive the rotation of the spit assembly about its longitudinal axis. Food items are skewered or otherwise fastened on the spits. Some configurations contain baskets suspended on the spits or baskets suspended between the plates instead of spits.

Referring now to FIGS. 2 and 3, the cooking apparatus 10 has an interior chamber 20 defined by opposing sidewalls, a floor and a ceiling. The interior chamber depicted in FIG. 2 is defined by two opposing walls 21 a and 21 b, a ceiling 25 c, a floor 25 f, a front wall 30 a and a back wall 30 b. In one embodiment, the front wall 30 a is also the door 14. In an embodiment, the floor 25 f is comprised of two planar substrates 26 joined at a common side at an angle so as to define a concave-like surface, such as a trough. The trough either extends side to side or front to back. A depending region of the trough terminates in an opening 27 which is positioned superior from the grease collection basin 29. The combination of substrates 26 and basin 29 create a grease trap. The basin 29 collects cooking by-products consisting mostly of fats, oils, and grease. Further, the basin 29 is angled towards an outlet 32, such as a tap or spout, (as seen in FIG. 1) so that the fats, oils, and grease can be removed from the cooking apparatus.

Plenum Detail

As can be seen in FIG. 3, a heat tolerant webbing or similar solid partition is positioned within the cavity 20 so as to physically isolate substantially the entire inside surface of the rear wall 30 b from the cavity. This partition, or dividing member, 40 therefore separates the interior cavity 20 into a cooking space 45 and an air plenum 50. In the embodiment shown, the dividing member 40 is comprised of flat and planar portions and is mounted between the two opposing walls 21 a and 21 b. The inventors have found stainless steel to be a suitable material for the construction of the walls of the oven and the diving member; however, other materials with similar heat tolerance and corrosion resistance may also be used. Additionally, the dividing member may be made from a material that acts as a radiant barrier such that the thermal radiation reflects from the dividing member back to the interior of the cooking cavity. The dividing member can be attached to the two opposing walls 21 a and 21 b in a variety of suitable ways including, but not limited to, bracket mounts, welding, brazing, screws, and rivets. Alternatively, a superior end of this dividing member 40 is attached to structures proximal to the ceiling 25 c of the cavity so as to be suspended within the cavity. In one embodiment, means for varying the depth of the plenum space are further provided. The dividing member can be reversibly attached to structures within the cavity 20 in a snap-fit, tongue and groove, or clamp configuration.

The dividing member 40 is comprised of a first portion 40 a and a second portion 40 b. The first portion 40 a and the second portion 40 b are continuous and can be integrally molded to each other. The first portion 40 a is primarily vertically oriented and spatially disposed of the back wall 30 b so as to be situated in a medial position compared to the back wall. The second portion 40 b is primarily horizontally oriented and spatially disposed of the ceiling 25 c. Between the first portion 40 a and the second portion 40 b is a mid- or transition-region 40 c, which connects the first portion 40 a and the second portion 40 b at an angle to position the first and second portions at a predetermined angle to each other. While the predetermined angle is determined by the configuration of the cavity, in the embodiment shown, that angle is approximately 90 degrees.

Generally, the first and second portions are arranged to be parallel with the cavity surfaces with which they are in close spatial relation. In the case of a rectangular shaped cavity, as depicted, the first portion 40 a and the second portion 40 b are arranged at approximately right angles to each other. For example, the transition region 40 c forms an angle α with the first portion 40 a and an angle β with the second portion 40 b. As depicted in FIG. 3, α and β are both approximately 135°; however, lesser or greater angles are envisioned. The transition region 40 c helps to minimize airflow restriction within the plenum. In this way, the dividing member 40 provides an air plenum 50 along the back wall 30 b and the ceiling 25 c.

FIG. 4 depicts the ceiling 25 c of the cooking apparatus 10. A plurality of air handling units 55 is positioned within the plenum and proximal to both the transition region 40 c of the dividing member and the ceiling 25 c. Such air handling units 55 include negative pressure devices, such as vacuum pumps, muffin fans, or similar suction devices, which impart a negative pressure within the plenum as a means to draw air into it from inferior regions of the cavity 20.

In the embodiment shown, the air handling units 55 are placed on the ceiling 25 cin the region proximal to the back wall 30 b. As depicted in FIG. 4, the air handling units 55 are two centrifugal fans. The air handling units 55 move the air within the plenum at a speed of between about 400 feet per minute and about 900 feet per minute. Preferably, about 600 to about 800 feet per minute, and most preferably, the air handling units 55 move the air at a speed of about 700 feet per minute.

Heating Element Detail

In a preferred embodiment of the invention, a plurality of heating elements 56 comprising a single heat source is centrally located on an inwardly facing surface of the ceiling 25 c. “Single heat source” as used in the specification refers to a plurality of heating elements that are generally located in the same region of the cooking apparatus and that are controlled by a single thermostat. As depicted in FIG. 4, an embodiment of the heating elements 56 are a plurality of “U” shaped elements, extending from one wall of the cavity to its opposing wall (in this case from the side wall 21 a to side wall 21 b). The elements are mounted to the ceiling 25 c via supports 57.

In a preferred embodiment, the plurality of heating elements 56 are tubular heaters encapsulating coils of resistance wire. The resistance wire is encapsulated to prevent their rapid oxidation. For example, the resistance wire of the heating element 56 depicted herein may be encapsulated by a material capable of withstanding temperatures required to effect proper cooking Suitable encapsulating material includes, but is not limited to powder, which is typically magnesium oxide, and then enclosed in a sheath of copper, steel, stainless steel, or Incoloy. The inventors have found an Incoloy sheath to be preferable in that it withstands temperatures up to 1800° F. However, a different sheath could be used depending on the operational temperature requirements of the desired cooking apparatus. The heating elements 56 are mechanically supported via a plurality of ports 58 on one of either of the sidewalls. As depicted in FIG. 2, the heating elements 56 are supported by ports 58 on the left sidewall 21 b. The heating elements 56 are in electrical communication with a control unit, which is in turn connected to a power source (the control unit and power source are not pictured).

The inventors have established a relationship between the Watt density of the heating element 56 and its failure rate. Specifically, the inventors have found that a Watt density of between approximately 20 W/in² and 35 W/in², and preferably 30 W/in², at the outside diameter of the heating element 56 drastically decreased the failure rate of the heating element 56 as compared to conventional oven heating elements having a Watt density of 50-60 W/in². The inventors also found that the lower Watt density also has the additional benefit of producing more useful radiation, i.e., radiation primarily in the 3-10 μm range.

Returning to FIG. 3, a first space, or gap, S is provided between the bottom of the first portion 40 a of the dividing member 40 and the substrate 26. The space S is an inferior or first opening at the depending end 41 of the divider 40 forming the plenum 50.

In operation, the air handling devices 55 draw air from the bottom of the cooking space 45, through the first space S, and up the plenum 50 along the back wall 30 b The air is then directed through the plenum 50 over the transition region 40 c and then along the ceiling 25 c. As the air passes along the ceiling 25 c, it comes in contact with the heating elements 56, which heats the air. Some air is expelled through a void 59 in the second portion 40 b of the dividing member 40. The remainder of the air is expelled from the plenum 50 back into the cooking space 45 at a second space S′ which is positioned proximal to the second end 43.

FIG. 5 shows the flow of air (dotted line with arrows) in the plenum 50. This air flow pattern serves two purposes. First, by drawing cooler air from the bottom of the chamber and expelling it at the top of the chamber, the heated air is forced to circulate throughout the entire length of the chamber. This provides a more uniform air temperature in the cooking space 45. For instance, chickens are typically cooked at 450° F. Air at the bottom of the chamber enters through the first space S at approximately 350° F. and exits through the second space S′ and void 59 at approximately 550° F. Thus, the chamber is maintained at the optimal temperature for roasting chickens throughout the cooking process. In one embodiment of the present invention (not shown), the spit assembly 19 rotates upwardly toward the second gap S′ and then in a direction towards the back wall 30 b, which is clockwise in the depiction of FIG. 3. This provides a means for drawing air from where it is expelled from the plenum at the front of the oven to the back of the oven, thereby further homogenizing the air temperature in the cooking space 45.

Second, the air flow creates an air curtain around the heating elements 56 that reduces the amount of grease splatter that reaches the heating elements 56. This invented combination of the novel air flow pattern that creates an air curtain around the heating elements and the lower Watt density discussed supra protects the heating elements from failure as a result of grease splatter.

Because a heating element 56 will invariably produce thermal radiation during operation, the void 59 in the second portion 40 b of the dividing member 40 allows that radiant energy to be put to use in the cooking process. As can be seen in FIG. 3, the void 59 is an adjustable open area within the second portion 40 b of the dividing member 40. The void 59 is positioned such that it allows the radiant heat from the heating elements 56 to pass onto the food that is rotating on the spit assembly 19. The center of the void 59 is preferably placed over the top of the spit assembly, which is generally circular in shape.

Referring now to FIG. 6, the width W of the void 59 is selected such that between about 20% and about 80% of the heating elements 56 are exposed. Preferably, between about 40% and about 60% of the heating elements are exposed. In this way, the air curtain effect can be maintained, and the food is not over-exposed to radiant energy.

In another embodiment depicted in FIG. 7, the size of the void 59 can be manipulated through the use of a plurality of sliding panels 60. The sliding panels 60 are nested in sheaths or pockets 62 formed into the second portion 40 b of the dividing member 40. The sliding panels 60 can be protracted to cover more heating elements 56 or retracted to expose more heating elements. A single sliding panel 60 can be provided that covers all or a substantial amount of the void 59, or opposing sliding panels 60 can be provided, wherein each panel 60 covers about half of the void 59 space. In this way, the sliding panels 60 can be customized to provide more or less radiant energy to the food on the spit assembly 19. Preferably, the sliding panels can be retracted or extended to expose between about 0% and about 80% of the heating elements 56.

A salient feature of the present invention is the shape of the void edge 63. The void edge 60 can be neutral or angled in a variety of ways to produce specific air flow effects. This void edge can be each or one of the leading edges of the sliding panels, discussed supra.

FIGS. 8A-8E show possible combinations of angled void edges 63 that provide different airflow dynamics, which can encourage airflow into the cooking cavity or discourage airflow into the cavity. As shown in FIG. 8A-8E, airflow goes from right to left, i.e., the same direction as shown in FIG. 5. FIG. 8A depicts neutral edges, which neither encourages nor discourages airflow into the cooking cavity.

FIG. 8B depicts the upstream edge 63 a encouraging airflow into the cavity, while the downstream edge 63 b is blocking reflected airflow from the cavity. This arrangement would create a strong air curtain, reducing the amount of grease that reaches the heating elements 56. FIG. 8C depicts the upstream edge 63 a discouraging airflow into the cavity, while the downstream edge 63 b encourages airflow into the plenum. This arrangement is designed to keep the most air in the plenum, which also causes more air to pass over the heating elements. FIG. 8D depicts both the upstream edge 63 a and downstream edge 63 b angled in a downward position. This arrangement effectively increases the volume along the plenum over the void 59, which, according to the Venturi effect, causes the airflow to slow over the void 59. Slower airflow creates higher pressure, which increases the effect of the air curtain. FIG. 8E depicts both the upstream edge 63 a and downstream edge 63 b angled in the upward position. This arrangement is the opposite of FIG. 8D and causes airflow over the void to increase in speed, which reduces pressure over the void 59. The increased speed keeps more air in the plenum, and the reduced pressure draws air in from the cooking cavity. Thus, this arrangement forces more air over the heating elements 56.

If the sliding panels 60 are used, then the void edge 63 and the panel edge are the same component. Thus, the panel edges can be neutral or angled in the same way as the void edge 63. In one embodiment of the invention, the panels 60 can be removed from the sheath 62. With two angled, removeable panels 60, all of the combinations of air flow patterns as depicted in FIGS. 8B-8E could be achieved based on how the user inserts the panels 60 into the sheaths 62.

Void Covering Embodiment

In some applications, the user may want to place a cover over the void 59 or plurality of apertures, which in combination comprise the void. Possible covers for the void include meshes, screens, expanded metal, and other partially open materials. These materials would limit the amount of heat flowing through the void 59, while still allowing a substantial amount of the radiant energy to pass onto the food. In some embodiments, the entire second portion 40 b of the dividing member is made of such partially open materials. As discussed supra, some of the apertures may be filled by infrared transparent material to prevent splattering, while simultaneously allowing IR transmission.

In another embodiment that can be seen in FIG. 9, a transparent material 65 is placed over a single aperture defining the void 59, and defines portions of the horizontally disposed plenum space The transparent material 65 is thus intermediate the heating elements 56 and the food items rotating on the spit assembly 19. The transparent material 65 allows the wavelengths of energy that comprise the thermal radiation to pass through it and onto the food items. In that way, the heating elements 56 are shielded from grease splatter yet simultaneously provides both convective and radiative heating.

The transparent material 65 can be placed within the second portion 40 b of the dividing member 40 in a variety of ways. In one embodiment, the transparent material 65 is removable and is simply placed over the void 59. In another embodiment, the transparent material 65 is inlayed into a supporting frame 67 formed into the second portion 40 b so as to be countersunk. In still another embodiment, the entire second portion 40 b is made of the transparent material 65.

A variety of suitable transparent materials 65 can be used in the cooking apparatus 10. The transparent material 65 must be transparent to radiation in the infrared spectrum, which corresponds to radiation with a wavelength from about 0.7 microns (μm) to about 1000 μm. Further, a suitable material will be able to withstand temperatures as high as 1400° F. Additionally, the material should be able to withstand the moist and potentially corrosive environment on the inside of the cooking apparatus, and it should be easy to clean. Suitable substrates comprising radio transparent or radio-lucent material include glass, plastic, wire mesh, ceramics, silicon, germanium, zinc selenide, zinc sulfide, sodium chloride, cesium iodide, and combinations thereof. Various IR-transparent or lucent materials can be inserted in the various voids in the plenum, depending on the IR radiation amount and wavelength desired. Suitable materials for the transparent material 65 include glass, ceramics, and Pyrex®. A preferable material is TEC glass.

Pass-Through Embodiment

FIG. 10 depicts a pass-through embodiment of the present invention that features a rear door 75 in conjunction with the front door 14. The two door design allows for pass-through of food items. The advantage of a pass-through design is that the preparation and serving of food can be physically isolated from each other. For example, rotisserie ovens are frequently used to cook chicken. Uncooked chicken is one of the leading causes of salmonella food poisoning. By using a pass-through design, a chef can prepare the uncooked chicken in the kitchen area, while the server can access the cooked chicken from the serving area. In this way, the raw chicken juices and drippings are isolated in the kitchen area, and the risk of salmonella contamination is greatly reduced.

In the pass through embodiment, the first portion 40 b of the dividing member 40 is mechanically joined to the rear door 75. As can be seen in FIG. 5, when the rear door 75 is closed, the first portion 40 a of the plenum 40 is in its position depicted in FIG. 3 so as to provide an air channel for circulation of air throughout the cooking apparatus. As can be seen in FIG. 10, the first portion 40 a is joined to the rear door 75 by two side panels 77. The side panels can be integrally molded into the rear door, welded to the rear door, mechanically fastened to the rear door, such as by screws, rivets, or pins, or attached via any other similar or suitable means. Alternatively, the first portion 40 a of the divider can be slidably received by portions of the door. In this instance, the side panels 77 are integrally molded to the first portion 40 a. The side panels 77 terminate in a flange for reversible mating with the access door. In one embodiment, the flanges contain keyhole slots adapted to receive matching pins formed into the access door. In this way, the first portion 40 a of the diving member 40 can easily be removed for cleaning and maintenance.

When the access door 75 is in the closed position, the first portion 40 a of the plenum 40 is maintained in close proximal relationship to the transition region 40 c. In this way, air is prevented from escaping from the plenum 50. In some embodiments, the transition region 40 c features a lip that overlaps the first portion 40 a of the dividing member 40.

As can be seen in FIG. 7, the rear door 75 opens about a vertical axis on the rear, righthand side of the unit; thus, fasteners are preferably placed on the lefthand side of the rear door. However, the fasteners could also be placed along the top or bottom of the door, or fasteners could be placed around all three edges. A suitable fastener would provide tight mechanical engagement between the rear door 75 and the housing 12. In a preferred embodiment, the fastener is a magnetic latch. The magnetic latch consists of a magnet located on the inside of the rear door 75 near the end of the door featuring a handle 79. A matching strip of flat mild steel bar is placed on the exterior of the housing such that the strip opposes the magnetic bar on the rear door 75. Other fasteners can also be used such as a variety of latches, including a bolt latch, a hook and eye latch, and a draw latch; door bars; and combinations thereof.

Aside from the foregoing description of a cooking apparatus 10 with a heating element 56 on the ceiling 25 c, the heating element 56 could be placed on the back wall 30 b of the cooking apparatus 10. In this embodiment, the void 59, cover, or transparent material 65 would instead be placed in the first portion 40 a of the dividing member 40. Other placements are also possible. For instance, the heating element 56 could be placed under the floor 25 c, proximal to the front wall or proximal to the side walls of the cooking apparatus 10.

As can be seen in FIG. 3, an insulated roof panel 82 is provided above the ceiling 25 c. This provides a means for keeping the exterior surface of the top of the housing cool enough to avoid combustion with any materials with which it comes in contact. An air shaft 84 is fed by moving air from the air handling units 55. The air in the air shaft 84 exits the left side of the oven through louvered openings (not shown).

FIG. 3 further shows that opposite the second end 43 of the second portion 40 b of the plenum terminates is a fin, vane, or baffle 85. This baffle 85 is provided on the interior of the cavity 20, proximal to the second space S′. The baffle 85 directs air towards the food items on the spit assembly 19. Further, when the oven is opened, the baffle 85 directs air inwardly, which prevents the operator from experiencing a blast of hot air upon opening the oven door. The baffle 85 is an optional feature and is not required for the operation of the cooking apparatus 10.

Thus, a cooking apparatus has been provided in which a single heat source provides both convective and radiative heating. The cooking apparatus features a novel air circulation design that improves convective heating by homogenizing the cavity temperature. The design employs a dividing member that defines a plenum, wherein the plenum draws air from the bottom of the cavity, moves the air over the heating elements, and expels it into the top of the cavity. The dividing member also features a void located intermediate of the heating element and the food items rotating on the spit assembly. The void allows the thermal radiation produced by the heating element to be used to crisp and brown the skin of the food item. The heating elements are protected from burnout in two ways: (1) the heating elements have a lower Watt density at their outer surface and (2) the novel air flow design creates an air curtain around the heating elements, partially shielding them from grease splatter. Thus, the reliability and consistency of the cooking apparatus is greatly improved.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the invention, they are by no means limiting, but are instead exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112(f) unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.

As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” “greater than,” “less than,” “more than” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. In the same manner, all ratios disclosed herein also include all subratios falling within the broader ratio.

One skilled in the art will also readily recognize that where members are grouped together in a common manner, such as in a Markush group, the present invention encompasses not only the entire group listed as a whole, but each member of the group individually and all possible subgroups of the main group. Accordingly, for all purposes, the present invention encompasses not only the main group, but also the main group absent one or more of the group members. The present invention also envisages the explicit exclusion of one or more of any of the group members in the claimed invention. 

The embodiment in which an exclusive property right or privilege is claimed is described as follows:
 1. A cooking apparatus, said apparatus comprising: a. a cooking cavity, wherein the cavity is defined by a front wall, a back wall that opposes the front wall, two opposing side walls, a ceiling, and a floor that opposes the ceiling; b. a substrate for supporting a food item, the substrate substantially enclosed by the cavity; c. a plurality of heating elements located proximal to the ceiling of the cavity; d. a dividing member, said dividing member comprising: i. a first portion spatially disposed from the back wall of the cavity; ii. a second portion spatially disposed from the ceiling of the cavity, wherein the first portion and second portion are continuous and define a plenum that extends from an area proximal to the bottom of the back wall to an area proximal to the top of the front wall; and iii. a void region located in the second portion, wherein the void region is intermediate the plurality of heating elements and the substrate; and e. at least one air handling unit located on the top portion of the cavity proximal to the back portion.
 2. The apparatus of claim 1, wherein the plurality of heating elements are tubular heaters.
 3. The apparatus of claim 2, wherein the tubular heaters are made from Incoloy.
 4. The apparatus of claim 2, wherein the tubular heaters have a Watt density of between 20 and 35 W/m² at the outside diameter of the pipe.
 5. The apparatus of claim 1, wherein the cooking apparatus has a pass-through design such that the front wall is a door and the back wall is a second door.
 6. The apparatus of claim 5, wherein the first portion of the dividing member is removably attached to the second door.
 7. The apparatus of claim 1, further comprising a baffle depending from the ceiling and proximal to the front wall.
 8. The apparatus of claim 1, wherein the void region exposes about 20% to about 80% of the heating elements.
 9. The apparatus of claim 1, wherein the void region is covered by an infrared transparent material.
 10. The apparatus of claim 9, wherein the infrared transparent material is selected from the group consisting of ceramic, Pyrex®, and TEC glass.
 11. The apparatus of claim 1, wherein the substrate for supporting a food item is a spit assembly.
 12. The apparatus of claim 1, wherein the at least one air handling unit is at least one centrifugal fan.
 13. The apparatus of claim 12, wherein there are two centrifugal fans.
 14. The apparatus of claim 1, wherein the front wall is also a door.
 15. The apparatus of claim 1, wherein the plenum has an air intake proximal to the bottom of the back wall and an air outlet proximal to the top of the front wall.
 16. The apparatus of claim 1, wherein the dividing member further comprises a transition region between the first portion and the second portion, wherein the transition region joins the first portion and the second portion and wherein the transition region and first portion form a first angle and the transition region and second region form a second angle.
 17. The apparatus of claim 16, wherein the first angle and the second angle are both between 130° and 140°.
 18. The apparatus of claim 1, wherein the void region is covered by retractable panels.
 19. The apparatus of claim 18, wherein the retractable panels have angled leading edges.
 20. A cooking apparatus, said apparatus comprising: a. a cooking cavity, wherein the cavity is defined by a front wall, a back wall that opposes the front wall, two opposing side walls, a ceiling, and a floor that opposes the ceiling; b. a substrate for supporting a food item, the substrate substantially enclosed by the cavity; c. a plurality of heating elements located proximal to the back wall of the cavity; d. a dividing member, said dividing member comprising: i. a first portion spatially disposed from the back wall of the cavity; ii. a second portion spatially disposed from the ceiling of the cavity, wherein the first portion and second portion are continuous and define a plenum that extends from an area proximal to the bottom of the back wall to an area proximal to the top of the front wall; and iii. a window region located in the first portion, wherein the window region is intermediate the plurality of heating elements and the substrate; and e. at least one air handling unit located on the top portion of the cavity proximal to the back portion. 